We need capnproto-lix to be provided by callPackage, otherwise it won't
be spliced and the same (built for the cross host platform) for both
buildInputs (correct) and nativeBuildInputs (incorrect). We thus move it
into the overlay.
A similar problem exists for the lowdown build. We thus use callPackage
to override it as well. This is horrible (especially because it means we
need to pass the enableDarwinSandbox package argument through
ourselves), but at least it builds...
Fixes: https://git.lix.systems/lix-project/lix/issues/939
Change-Id: I802152072d852903401ef701f526195aa99475f2
Linus Heckemann
52ef1181f0